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1.
An overview is given of decision making frameworks for Ecological Risk Assessment (ERA) used for sediment in a number of European
countries. These frameworks fall into two categories:
The first approach is usually part of an evaluation of whether remediation is needed in order to control or reduce the ecological
risks of sediment pollution in a given location. The purpose of the second approach is to evaluate the risks of possible (unconfined)
disposal options for dredged sediment (including sediment that is dredged for navigational reasons). Important aspects are:
相似文献
• | Biological Effects-Based Assessment of in situ risks (referred to as in situ BEBA); |
• | Biological Effects-Based Assessment of the ex situ quality of dredged sediments (referred to as ex situ BEBA). |
• | Objectives for sediment management; |
• | The level of integration of BEBA in legal frameworks; |
• | The use of chemical (numeric) SQG’s in BEBA and their integration with biological information; |
• | The criteria used to infer effects and to classify sediment quality. |
2.
Willie Peijnenburg Else Sneller Dick Sijm Johannes Lijzen Theo Traas Eric Verbruggen 《Journal of Soils and Sediments》2002,2(4):169-173
Conclusions On the basis of the discussion of the fact sheets during the workshop, it is advised to:
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– | •implement the proposed method for normalization of levels of organic compounds on the basis of elementary carbon present in the substrate towards (Dutch) standard sediment and standard soil; |
– | •decide to modify the existing standards for local natural background levels, as a short-term solution to substitute for the current practices in the Netherlands of normalization on the basis of so-called standard soil or sediment. This provided that a trajectory for the incorporation of bioavailability is initiated; |
– | •establish clusters of research groups that are commissioned to prepare proposals for an implementation of the six topics for which it is foreseen that implementation is possible within 1–3 years, such as DOC-correction for copper in water (Box 1). This included an investigation of ways of financing the necessary research activities; |
– | •look for broader (international) support for further research activities and ways of implementation within an international framework (EU) for all options with a timeframe >3 years. The recommendations of the workshop might be one of the criteria for the selection of research proposals within the area of bioavailability; |
– | •stay alert on new developments within the broad area of bioavailability and continue looking for ways of implementing the most promising new insights. |
3.
Conclusions
German federal research plan from the German Federal Ministry for the Environment, Wildlife Conservation and Nuclear Safety
- Treatment and utilization of wastes. Research report 297 33 911 - UBA-FB 000074. Original title: Charakterisierung und Verwertung
von Abf?llen aus der Massentierhaltung unter Berücksichtigung verschiedener B?den. Stoffeintrag in B?den durch Tierarzneimittel
und pharmakologisch wirksame Futterzusatzstoffe unter besonderer Berücksichtigung von Tetrazyklinen. A research article on
this topic follows in JSS No. 2.
DOI: http://dx.doi.org/10.1065/jss2001.02.006. By courtesy of the German Federal Environmental Agency (Umweltbundesamt - UBA).
The complete research report is available as UBA-TEXTE 44/00 (ISSN 0722-186X) by payment of DM 20,00 (Euro 10,26), account
no. 4327 65-104, Postbank Berlin (BLZ 10010010), Fa. Werbung und Vertrieb, Ahornstra?e 1-2, D-10787 Berlin, Germany 相似文献
– | •In intensive animal production, a considerable proportion of the livestock population must be expected to receive animal pharmaceuticals. |
– | •The administration of pharmacologically-active feed additives has been influenced through the revocation of approval for some individual substances over the last few years. Aside from the substitution of these forbidden substances, further reductions in the use of antibiotic growth promotors can be expected primarily because of economic reasons. |
– | •Animal pharmaceuticals frequently consist of so-called older preparations whose ecotoxicological potentials have only been investigated inadequately. |
– | •High elimination rates of the active substances and their stability during storage, which could be demonstrated for tetracyclines, might also lead to a significant incorporation of these substances into the soil even when they are employed correctly. In the future, ecotoxicological investigations should be demanded in cases where the EMEA/CVMP trigger values (which are substantially lower) have been exceeded, a procedure which is currently only required for the newly approved agents. |
– | •There is presently a considerable need for research into the environmental fate of these older preparations and their ecotoxicological effects. Here, it will be especially important to take the degradation and transformation processes in the soil into account, as well as especially considering the consequences on the microbiological impacts affecting the soil. |
– | •Improved transparency in the application of these substances, in the sense of a quantitative’registration of the animal pharmaceuticals (especially the older preparations) which are employed, as well as the environmental monitoring of animal pharmaceuticals (e.g. in groundwater and surface water), would considerably improve the significance of the basic data for future appraisals. |
4.
5.
Anaerobic sediment potential acidification and metal release risk assessment by chemical characterization and batch resuspension experiments 总被引:1,自引:0,他引:1
Background, Aim and Scope Sediments act as a sink for toxic substances (heavy metals, organic pollutants) and, consequently, dredged materials often
contain pollutants which are above safe limits. In polluted anaerobic sediments, the presence of sulphides and redox potential
changes creates a favorable condition for sulphide oxidation to sulphate, resulting in potential toxic metal release. The
oxidation reaction is catalyzed by several microorganisms. Some clean up measures, such as dredging, can initiate the process.
The aim of the present work is to assess the acidification and metal release risk in the event of sediment dredging and also
to compare two different acid base account techniques with the resuspension results. The oxidation mechanism by means of inoculation
with an Acidithiobacillus ferrooxidans strain was also evaluated.
Methodology The sediments were chemically characterized (pH; organic oxidizable carbon; acid volatile sulphides; total sulphur; moisture;
Cr, Cu and Zn aqua regia contents). A metal sequential extraction procedure (Community Bureau of Reference, BCR technique)
was applied to calculate the Acid Producing Potential (APP) and Acid Consuming Capacity (ACC) of the sediment samples through
Fe, Ca2+ and SO4
2− measurements. The acid base account was also performed by the Sobek methodology (Acid producing potential — AP — calculated
with total sulphur and neutralization potential — NP — by titration of the remaining acid after a reaction period with the
sample). Fresh sediments were placed in agitated shake flasks and samples were taken at different times to evaluate pH, SO4
2− and Cr, Cu, Zn and Fe2+ concentration. Some of the systems were inoculated with an Acidithiobacillus ferrooxidans strain to assess the biological catalysis on sulphide oxidation.
Results Sediment chemical characterization showed high organic matter content (5.4–10.6%), total sulphur (0.36–0.86%) and equivalent
CaCO3 percentages (4.5–8%). pH was neutral-alkaline for all of the samples. AVS content was high except for sample 5. The acid
base account obtained with the two methods gave different results for the acid generating risk of the samples. A decrease
of 0.4 to 3.1 pH units was measured in the agitated shake flasks. In all of the systems, sulphate concentration increased
(2,100–2,200 mg L−1 to 2,500–3,000 mg L−1), and positively correlated with the initial total sulphur content of the samples in the inoculated flasks. Cu and Cr in
solution were not detected in most of the sampling occasions (<0.5 mg Cu L−1 and <0.5 mg Cr L−1). Zn reached high concentrations (up to 11.8 mg L−1). For every system — except sediment 1 — the lowest pH registered was similar in comparison to inoculated and control systems.
The inoculation effect was mostly evidenced in the systems by a higher sulphate release rate compared to the control systems.
Discussion The BCR method categorized all of the samples as potentially acid generating material. The Sobek method using NPR (NP/AP)
criteria classified sample 3 as a possible acid generator and samples 1, 2 and 5 with a low acid generation potential. Despite
this, all the samples acidified the media in the kinetic tests in at least one of the conditions employed in this work. It
would seem that NPR and NNP (NP-AP) risk classification criteria should not be directly used with anaerobic sediments. Appropriate
classification levels for sediments should be developed considering the different sulphide reactivity between rock and sediments.
Sediment oxidation can cause acidification, which is partially explained by sulphide oxidation. In the samples studied, we
found a positive correlation between sulphate increase in solution after oxidation and total sulphur content in the inoculated
systems. Significant amounts of Zn could be released to solution while Cr and Cu remained insoluble despite the pH decrease
observed. The low Cu and Cr mobility could be explained by the very low solubility of their hydroxides and high affinity for
organic matter and iron oxides/hydroxides that might form during sediment oxidation. Dredged sediment management and disposal
should be carefully planned.
Conclusions All of the sediment samples lowered the pH media in the laboratory batch resuspension experiments. However, both risk classification
criteria (NNP, NPR) from Sobek acid base account were not able to predict the samples’ behavior as accurately as the BCR derived
base account. The inoculation effect was mostly associated with a higher sulphate release and not to a lower pH due to acid
base equilibrium.
Recommendations and Perspectives Appropriate risk classification levels for sediments should be developed considering the different sulphide reactivity between
rock and sediments.
ESS-Submission Editor: Dr. Sabine Ulrike Gerbersdorf (sug@st-andrews.ac.uk) 相似文献
6.
DNA bound on clay minerals, sand, and humic acids has been shown, both in vitro and in situ, to be capable of transforming bacteria and to resist degradation by nucleases, which could result in the crypticity of genes in soil and other natural habitats. To determine where DNA is bound on clay minerals, which may help to explain how bound DNA becomes resistant to degradation by nucleases but retains the ability to transform competent cells, chromosomal DNA from Bacillus subtilis bound on montmorillonite (M) and kaolinite (K) was examined by X-ray diffractometry and transmission and scanning electron microscopy. X-ray diffraction analysis showed that the basal spacings of M and K were not altered, indicating that this DNA did not significantly intercalate the clays. Scanning and transmission electron microscopy showed that the binding of this DNA was primarily on the edges of M and K, although some binding was also apparent on the planar surfaces. Based on the results of these studies, it is postulated that:
相似文献
1. | extension from the edges of the clays enables the unbound end of DNA to interact with receptor sites on competent cells and result in their transformation; and |
2. | binding on clays alters the electron distribution and/or conformation of DNA, which reduces its hydrolysis by nucleases. |
7.
W. Mill 《Water, air, and soil pollution》1995,85(4):2547-2552
Since 1990 the Institute for Ecology of Industrial Areas, acting as National Focal Center, is actively involved in an international research programme aimed at the calculation and mapping of critical loads of acidifying compounds. Following the methodological guidelines elaborated under the leadership of UN/ECE Task Force on Mapping and Coordination Center for Effects, national maps of critical loads and their exceedances for acidity, sulphur and nitrogen have been produced. These maps have already been utilized in derivation of European maps of critical loads of acidity and sulphur submitted to the UN/ECE LRTAP Convention as scientific input to the negotiations on the Second Sulphur Protocol. The lessons learned from the critical loads mapping exercise can be summarized as follow:
相似文献
| the majority of Polish territory is covered with forest soils sensitive to acidification at an average Central European level; |
| the exceedances of critical loads, estimated on the basis of national deposition data reveal the tune changes of ecological risks on the territory of Poland as a reflection of economic transition. The significant difference in the scale of those risks (measured by the percentage of the country territory with the maximum exceedances of critical loads) that appear in the period between 1987, representing the period of central planned economy and 1990, representing the early transition phase to a market economy, is particularly notable. |
8.
9.
Control of geochemical mobility of arsenic by liming in materials subjected to acid mine drainage 总被引:2,自引:2,他引:0
Renato P. de Andrade Bernardino R. Figueiredo Jaime W. V. de Mello Julio C. Z. Santos Lorenza U. Zandonadi 《Journal of Soils and Sediments》2008,8(2):123-129
Background Acid mine drainage (AMD) results from the exposure of sulfide materials to atmospheric water and oxygen. In addition to AMD,
oxidation of arsenopyrite and other As-bearing sulfides can release arsenic (As) into the environment. In view of the risk
to living organisms due to contamination of ground and surface water sources with As, this work was carried out to evaluate
the effectiveness of lime (CaCO3) in controlling the dispersion of this metalloid in the environment.
Methods Partially oxidized samples of sulfide bearing materials from gold mines in Brazil were used to evaluate the arsenic mobilization
by leaching tests. Columns containing ground samples, with and without liming treatments, were leached with distilled water
every two weeks over a 156-day period.
Results and Discussion The acid-base accounting (ABA) static tests classified the samples as potential acid forming materials. In the treatments
without liming, As, Fe and S concentrations in the leachates were higher than after treatment with carbonate. Nevertheless,
the effectiveness of liming and As mobilization were lower in the sample containing goethite. A high correlation between Fe
and As concentrations in the leachates (r=0.749) suggests that iron (hydr)oxides retained arsenic in the solid phase. Oxidation
rates of As bearing sulfides were increased at low pH (2.0–3.9), probably due to the enhanced activity of bacteria (Acidithiobacillus) and decreased rate of Fe precipitation, thus reinforcing generation of acid water, and consequently releasing As.
Conclusions and Perspectives Our results corroborate the use of lime to control the dispersion of As in AMD-affected environments. However, the effectiveness
of the liming treatment seems to be dependent on the presence of iron (hydr)oxides in the sample. These findings can be useful
to remediate areas affected by acid mine drainage and arsenic mobilization in partially oxidized sulfide materials.
ESS-Submission Editor: Chengrong Chen, PhD (c.chen@griffith.edu.au) 相似文献
10.
The impact of storm water runoff on a small urban stream 总被引:2,自引:0,他引:2
Vilmantė Karlavičienė Sigita Švedienė Danutė Elena Marčiulionienė Peter Randerson Mindaugas Rimeika William Hogland 《Journal of Soils and Sediments》2009,9(1):6-12
Background, aim, and scope In urban areas, storm water runoff often transports various pollutants, some of which settle and form sediments. In order
to have the comprehensive view of the ecological state of storm water runoff recipients, both water and sediments of the stream
must be assessed. In the Baltic Sea Area, the Water Framework Directive & HELCOM Recommendations aim to prevent or minimise
pollution caused by harmful substances arising from storm water runoff, in order to promote the ecological restoration of
the Baltic Sea—one of the most vulnerable seas. The aim of the study was to investigate the toxicity of bottom sediments of
a small storm water runoff recipient focusing on the potential impact of successive discharges of urban storm water. Some
storm water runoff quality parameters and the toxicity of bottom sediments of recipients was studied in this research.
Materials and methods During 9 years, at four discharge points, minimum four grab samples per year at each discharge point were taken for chemical
characterisation. General parameters (pH, SS, BOD7, CODCr and TPH) in liquid phase samples were analysed according to standard methods. Annual limit values were taken from the Lithuanian
EPA requirements for the management of storm water runoff with a focus on prevention and control of contamination. Eleven
composite samples of stream bottom sediments, each consisting of ten sub-samples, were collected in 2006. Toxicity screening
from sediments was performed using the plant Lepidium sativum according to modified I. Magone’s methodology (Magone I, Bioindication of phytotoxicity of transport emission. In: Kachalova
O-L, Zinatne (eds) Bioindication of toxicity of transport emissions in the impact of highway emissions on natural environment. Riga, pp 108–116, 1989). The level of toxic impact of Lepidium sativum (compared to control) was assessed according to the modified method of Wang (Rev Environ Contam Toxicol 126:88–127, 1992).
Results The mean pH of urban storm water runoff does not vary much from neutral, but range values are quite different, from 4.0 up
to 8.7. The highest concentration of SS reached 800 mg L−1, TPH—2.4 mg L−1, BOD7—300 mg O2 L−1 and CODCr—1,400 mg L−1. The SS was above the limit in 64% of total amount of grab samples, TPH—37%, BOD7—41% and CODCr—55%. The toxicity analysis of the bottom sediments showed varying toxicity of bottom sediments along the stream. From nine
analysed samples of bottom sediments, 30% had weak toxicity, 30% medium and 30% strong toxicity on the test organism plant
L. sativum. There was one single sample with no toxic effects, so that the results showed that urban storm water has an unacceptable
environmental impact on recipients. It was also indicated that storm water runoff discharge alone is not the potential source
of toxicity of bottom sediments. The litter demonstrated a weak toxicity of bottom sediments as well.
Discussion Most local authorities do not consider storm water runoff discharges to be a matter of great concern because they believe
that surface runoff arising from rainfall is still relatively clean. The study showed that the current method of monitoring
storm water runoff quality by chemical analyses is not the best tool for environmental impact assessment and must be combined
with toxicity tests of bottom sediments of recipients.
Recommendations and perspectives To avoid the environmental impact of storm water runoff more attention should be paid to the development and implementation
of storm water runoff pollution prevention measures. The study implies that future research concerning the relationships between
storm water runoff deposit characteristics and biological activities must be developed to evaluate the contamination potential
of stream sediment deposits for local aquatic ecosystems. Further studies should be developed to characterise the activities
of the microbial community of storm water runoff sediments, and to monitor bioremediation in situ. 相似文献
11.
Richard W. Todd N. Andy Cole R. Nolan Clark William C. Rice Wen-Xuan Guo 《Biology and Fertility of Soils》2008,44(8):1099-1102
Cattle feedyards can impact local environments through emission of ammonia and dust deposited on nearby land. Impacts range
from beneficial fertilization of cropland to detrimental effects on sensitive ecosystems. Shortgrass prairie downwind from
an adjacent feedyard on the southern High Plains of Texas, USA changed from perennial grasses to annual weeds. It was hypothesized
that N enrichment from the feedyard initiated the cascade of negative ecological change. Objectives were to determine the
distribution of soil nitrogen and estimate N loading to the pasture. Soil samples were collected from 119 locations across
the pasture and soil total N (TN), nitrate-N and ammonium-N (AN) determined in the top 30 cm. Soil TN concentration decreased
with distance downwind from the feedyard from 1.6 ± 0.2 g kg−1 at 75 m to 1.2 ± 0.05 g kg−1 at 582 m. Nitrate-N concentration decreased within 200 m of the feedyard and changed little at greater distances. Ammonium-N
concentration decreased linearly (P < 0.001) with increasing distance from the feedyard from 7.9 ± 1.7 mg kg−1 within 75 m from the feedyard to 5.8 ± 1.5 mg kg−1 at more than 550 m from the feedyard; however, distance only explained 12% of the variability in AN concentration. Maximum
nitrogen loading, from 75 to 106 m from the feedyard, was 49 kg ha−1 year−1 over 34 years and decreased with distance from the feedyard. An estimate of net dry deposition of ammonia indicated that
it contributed negligibly to N loading to the pasture. Nitrogen enrichment that potentially shifted vegetation from perennial
grasses to annual weeds affected soil N up to 500 m from the feedyard; however, measured organic and inorganic N beyond that
returned to typical and expected levels for undisturbed shortgrass prairie.
相似文献
Richard W. ToddEmail: |
12.
Different authors in India and South East Asia treat dioecious species in the genus Momordica differently. The cultivated ‘bhat karela’ of East and North East India is referred to as Momordica dioica Roxb. by botanists and herbarium curators whereas agricultural scientists, in general, designate it as Momordica cochinchinensis Spreng. A critical study of 266 herbarium sheets housed at CAL and BSISH and in situ field studies at specific pockets in
the North East India followed by preliminary characterization revealed its correct identity as Momordica subangulata Blume subsp. renigera (G. Don) de Wilde. First hand information on its occurrence, taxonomy and distribution in India is given. The species was
found in wild as well as in homestead cultivation in North Eastern India and exemplify direct utilization of biodiversity
by indigenous people.
相似文献
K. Joseph JohnEmail: |
13.
Biomarker and hydrochemical characteristics of geogenic arsenic-contaminated aquifers at Datong Basin, northern China, were
analyzed to better understand the impact of organic matter (OM) biodegradation on arsenic enrichment in groundwater. The hydrochemical
characteristics of high arsenic groundwater from the Datong Basin indicate that arsenic mobilization and iron and manganese
oxide/hydroxide reduction were controlled by biodegradation of OM. The elevated value of alkalinity produced by microbial
oxidation of OM is another important factor for arsenic mobilization via competitive sorption. Bulk geochemistry of the sediments
shows that arsenic has close correlation with iron and manganese, indicating iron- and manganese-bearing minerals could be
the major pools for arsenic. Results of biomarker analysis reveal that all the sediments contained natural petroleum-sourced
hydrocarbons which may have undergone biodegradation, as suggested by the carbon preference index, C29 sterane, and the distribution pattern of hopanes. The presence of unresolved complex mixtures in all samples also indicates
the natural petroleum origin of hydrocarbons and the effect of biodegradation. At some depths (5.4–11.8, 31–33.2, and 40–48.4 m
below the land surface), the samples have low n-alkane content and no odd-over-even predominance, suggesting that indigenous
microbes within the aquifer can preferentially remove the petroleum-sourced n-alkanes. The bioavailability of organic carbon
is very important to promote the microbially mediated reductive dissolution of iron oxides/hydroxides and subsequent arsenic
release from aquifer sediment into groundwater. 相似文献
14.
Charles B. Heiser 《Genetic Resources and Crop Evolution》2008,55(1):9-13
I have concluded that my initial verification of a specimen recovered from the San Andrés archaeological site in Mexico as
domesticated sunflower was incorrect. The specimen in question is most likely the seed of a bottle gourd. As yet there is
no compelling evidence that the sunflower was grown as a food crop in Mexico prior to European contact. In addition, the complete
absence of any early historical record for the sunflower in Mexico argues against its presence in pre-Columbian times. Although
no dates or boundaries can be set, the wild sunflower may have grown in northernmost Mexico in early times. A southward range
expansion for the species is probably very recent, perhaps in the last few hundred years with the development of a modern
road system. The widely used common names of the sunflower in Mexico are in Spanish or with Spanish words in them, which suggests
that the sunflower is a post-contact arrival.
相似文献
Charles B. HeiserEmail: |
15.
Contamination history of suspended river sediments accumulated in oxbow lakes over the last 25 years 总被引:3,自引:2,他引:1
Ondrej Bábek Klára Hilscherová Slavomír Nehyba Josef Zeman Martin Famera Juraj Francu Ivan Holoubek Jirí Machát Jana Klánová 《Journal of Soils and Sediments》2008,8(3):165-176
Background, aims, and scope Embankment of meandering river systems in many industrial areas results in the formation of artificial oxbow lakes that may
act as perennial or intermittent traps for river sediments. Their deposits can be dated using a combination of historical
and stratigraphic data, providing a good means to study historical records of contamination transported by rivers. Contamination
history over the last few decades is of special significance for Central and Eastern Europe as it can reflect high pollutant
levels in the second half of the twentieth century and the subsequent improvement after the fall of the Iron Curtain. The
purpose of this study was to investigate recent sediments of an oxbow lake of the Morava River, Czech Republic, their stratigraphic
records, sediment architecture, and history of contamination.
Materials and methods Seven ground-penetrating radar (GPR) profiles and three sediment cores up to 4 m deep were studied. The stratigraphy of the
cores was inferred from visible-light spectrophotometry, X-ray radiography, grain size analysis, and semiquantitative modal
analysis of sandy fractions. The sediments were dated using the 137Cs mass activity and combinations of stratigraphic and historical data. The cores were sampled for concentrations of heavy
metals and persistent organic pollutants. Wet sampled, lyophilized, and sieved sediments were extracted and analyzed for heavy
metals by inductively coupled plasma mass spectrometry (ICP-MS) of aqua regia leachate and for persistent organic pollutants
by gas chromatography (GC-ECD and GC-MS).
Results Three distinct sedimentary sequences (S1, S2, and S3) were identified. The basal sequence S1 represents river channel sediments
deposited before the formation of the oxbow lake, most likely before the 1930s. The boundary between the S1 and S2 sequence
correlates with the level of sediment dredging from 1981 evidenced from historical data. The overlying sequences S2 and S3
represent a postdredging sediment wedge, which progrades into the lake. 137Cs dating revealed a distinct Chernobyl 1986 peak at ∼150 cm depth inferring sedimentation rates up to 7.7 cm/year. Sediment
contamination abruptly increased from the pre-1930s deposits to the post-1981 deposits. The concentration levels increased
two to five times for Pb, As, Zn, and Cu, about 10 to 15 times for Cr, Sb, and Hg, up to 34 times for Cd, and 25 to 67 times
for DDTs, PCBs, and PAHs. The concentrations of most contaminants remained approximately constant until the late 1980s when
they started to decrease slowly. The decreasing trends were most prominent for heavy metals and anthracene, less prominent
for DDTs, and almost absent for PCBs and most PAHs.
Discussion Different temporal and spatial patterns for various contaminants make it possible to distinguish between anthropogenic point
sources from local industry (anthracene, Cr, Cd), possible diffuse sources (most PAHs), and geological background (V, Co,
Ni, and Mo). The observed recent trends in heavy metal and persistent organic pollutant contamination are generally consistent
with data from other Central European rivers. The roughly balanced contamination levels in sediments from the lake and the
adjacent river channel suggest that the oxbow lake deposits reflect immediate levels of the contamination bound to suspended
particulate matter passing through the river.
Conclusions The investigated oxbow lake accumulated suspended sediment from Morava River, developing a thick sedimentary body. The sediments
offer a good time framework to study historical contamination of the river on a decade time scale. Continuous contamination
trends can be traced back to the early 1980s. The results show that stratigraphic analysis of cores has a good potential for
identification of uninterrupted historical trends and unconformities, e.g., due to dredging.
Recommendations and perspectives Oxbow lakes may provide an alternative to floodplains and reservoir deposits when studying river contamination history. High
sedimentation rates of up to 7.7 cm/year offer a very good stratigraphic resolution, making it possible to study contamination
patterns on annual or even seasonal time scales. On the other hand, oxbow lakes may represent long-term contamination stores,
which are unlikely to be redistributed by river erosion and, hence, may possess significant environmental risks for the farther
future. 相似文献
16.
Barbara Maliszewska-Kordybach Agnieszka Klimkowicz-Pawlas Bozena Smreczak Rafał Gałązka 《Water, air, and soil pollution》2012,223(2):687-697
During the intensive flood in May–June 2010, the floodplains in Little Poland Vistula Gap, used mostly for agriculture, were
waterlogged for a period of over 1 month. The aim of the study was to assess the effect of the flood on the level of contamination
of the soils in this region. The analysis included basic physicochemical soil properties, contents of ten metals, and concentrations
of 16 polycyclic aromatic hydrocarbons (PAHs). The studies cover two territories on opposite sites of the river Vistula (Wilkow
and Janowiec) differing in their areas (70 and 4.6 km2) and time of water logging (30 and 10 days). Forty soil samples were collected from both areas immediately after the flood
event from the upper (0–30 cm) soil layer together with four samples from the 30–60-cm depth layer. This was supplemented
by eight samples from the flood-deposited sediment layer (thickness, 2 cm). The concentrations of identified metals (As, Ba,
Cr, Sn, Zn, Cd, Co, Cu, Ni, Pb) at all the sampling points were below the Polish legal limits for the upper layer of soils
for agriculture use. The same regarded the median contents of nine PAHs compounds specified in the Polish regulations. In
both areas, the median contents of Σ16 PAHs (0.21–0.35 mg kg−1), Zn (10.3–10.6 mg kg−1), Pb (9.2–10.7 mg kg−1), and Cd (0.03 mg kg−1) were much below the mean concentrations of those contaminants in arable soils on the national and European levels. The results
show that this severe flooding episode in “clean” agricultural area had no immediate negative impact on the soils as regards
the basic physicochemical properties (organic matter content, acidity, nitrogen content) and did not result in excessive soil
contamination. 相似文献
17.
Ana Luisa Costa Susana M. Paixão Isabel Caçador Manuela Carolino 《Journal of Soils and Sediments》2007,7(6):418-425
Objective Microbial communities are a central component of trophic dynamics and biogeochemical processes on coastal systems, since most
of the processes in sediments are mediated by microorganisms and carried out by enzymes. Microorganisms play a key role in
decomposition processes in salt marsh sediments, although the significance of microbial dynamics is largely unexplored. A
culture-dependent (Ecoplate) and a culture-independent (extracellular enzyme activity [EEA]) approaches were evaluated in
their ability to distinguish the catabolic potential among sediments from Tagus estuary salt marshes with different proximities
to anthropogenic sources.
Methods Ecoplate was used to analyse the salt marsh community-level physiological profiles (CLPPs). Results were expressed as the
net area under the curve for each of the 31 response wells over a 3-day incubation period in two sediment horizons. The catabolic
profiles for salt marsh samples were analysed by Principal Component Analysis (PCA) and hierarchic clustering methods. EEA
was analysed by fluorescein diacetate (FDA) hydrolysis in two sediment horizons. The FDA is catalysed by extracellular enzymes,
i.e. esterases, lipases and partially by proteases. Results were expressed as μg g−1d wt h−1.
Results and Discussion In this study the CLPP and EEA data were not generally correlated. In Corroios salt marsh only in surface sediments higher
net areas corresponded to higher extracellular enzymatic activity, and in Alcochete deep sediments lower net areas corresponded
to lower enzymatic activity. Although EEA profiles more directly reflect the inherent activity of resident community in each
salt marsh sample, the CLPP profiles provide better assessments of diversity.
ESS-Submission Editor: Prof. Dr. Peter Schroeder, Institute of Soil Ecology, Department of Rhizosphere Biology, GSF — National Research Center for
Environment & Health, Ingolstaedter Landstrasse 1, 85758 Neuherberg, Germany (peter.schroeder@gsf.de) 相似文献
18.
Xi-Xiang Yin L. H. Wang R. Bai H. Huang Guo-Xin Sun 《Water, air, and soil pollution》2012,223(3):1183-1190
Synechocysis sp. PCC6803 is a unicellular blue alga which ubiquitously exists in aquatic system and is considered to play a role in arsenic
cycling. Our results showed that Synechocysis can accumulate arsenic as much as 1.0 and 0.9 g kg−1 DW when exposed to 0.5 mM arsenate and arsenite for 14 days, respectively. In addition, arsenic species in cells were assayed
under different exposure conditions and it was found that inorganic arsenic, including arsenate and arsenite, is the dominant
species. Organic methylated arsenicals can only be detected exposed to higher arsenic concentration range (100–500 μM). Arsenate
is the dominant arsenic species and presents more than 80% of the total arsenic in cells. Efflux of both arsenate and arsenite
was observed. When treated with 2.67 μM arsenite, Synechocysis can rapidly oxidize arsenite to arsenate and accumulate As rapidly. The observed arsenic oxidation in solute is solely caused
by cellular oxidation. Given the robust ability of As accumulation, it can serve as a phytoremediation organism to efficiently
remove arsenic from aquatic environments. 相似文献
19.
Dominic Standing Elizabeth M. Baggs Martin Wattenbach Pete Smith Ken Killham 《Biology and Fertility of Soils》2007,44(2):245-257
The scaling up of processes in the plant–soil–microbe system represents one of the greatest challenges facing environmental
scientists and yet is essential for sustainable land management worldwide. The latter encompasses, for example, the mitigation
of and adaptation to anthropogenic climate change, the bioremediation of industrially contaminated sites, catchment management
of human pathogens such as Escherichia coli O157 and integrated crop management on the farm. Scaling up is also essential for the regional and global biogeochemical
modelling that will inform policy-makers of the critical environmental factors driving climate change. Despite increasing
understanding of the links between gene expression and process on a microscale, there is still much progress to be made when
relating this to processes at the macroscale. In this paper, we explore the challenges this poses and examine key case studies
of successful up-scaling.
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Dominic StandingEmail: |
20.
Intention, Goal and Background Contaminated sediments represent a significant, worldwide environmental problem since they contain a mixture of different
xenobiotics and heavy metals. The presence of mixed contamination presents a unique set of obstacles for remediation efforts.
Often sediment remediation occurs as an ex-situ application (i.e., after dredging) in an attempt to minimize some of the problems.
However, dredging poses it’s own issues. It does not address contaminated water and often material is not completely removed
thereby leaving a long-term residual contamination source in the waterway.
Objective The potential of bio remediation to treat sediments contaminated with polycyclic aromatic hydrocarbons (PAHs), polychlorinated
biphenyls, and heavy metals was addressed. The primary objective was to assess two delivery mechanisms for microbial inoculation
to facilitate in-situ remediation of PAH contaminated sediments.
Methods Simulated river beds were constructed to mimic the Mahoning River. Contaminated sediment from the river was added to each
reactor at a uniform depth, followed by the addition of river water. Fifteen inoculation points were used in each simulated
river bed to ensure adequate microbial populations. One tank was inoculated with an acclimated bacteria solution as a free
suspension. The other tank was inoculated with an attached growth biofilm system. Sediment samples were taken throughout the
experiment and the percent PAH degradation determined. Water characteristics (DO, pH, bacterial activity, etc.) were also
tracked as corroborating evidence.
Results and Discussion The monitoring sites indicated that an attached growth system was more effective, and achieved a 99% PAH degradation efficiency
at some of the sampling sites. Tracking individual PAH compounds also indicated a higher overall microbial activity with the
attached growth system. This activity was evident by the formation and subsequent biodegradation of lower molecular weight
degradation byproducts. However, more of the sediment area was treated by the free suspension inoculum due to the ease of
microbial migration.
Conclusions The applicability of using an aerobic microbial consortium composed ofMycobacterium sp., Pseudomonas aeruginosa, andPseudomonas flourescens to treat contaminated sediment was demonstrated. In addition, it was found that introducing the consortium as an attached
growth was more effective than when delivered as a free suspension.
Recommendation and Outlook The results demonstrated that the consortium was effective at treating the PAHs present in the contaminated soil. An additional
study to evaluate the consortium’s effectiveness at remediating the PCB present in the sediment is warranted. Optimization
of the consortium-nutrient combination could enable a treatment approach to effective for all the organic contaminants present.
Although this would not address the heavy metals present in the sediment, it would afford a great opportunity at remediating
a severely contaminated sediment system. 相似文献